Device and method for extracting, distilling and separating propane and propylene

Abstract

The invention discloses a device and a method for extracting, distilling and separating propane and propylene and aims to solve the technical problems that both the equipment investment and energy consumption of the existing low-pressure distilling method for separating propane and propylene are increased and the high-pressure distilling method for separating propane and propylene needs more theoretical plate number and large reflux ratio. The device for extracting, distilling and separating propane and propylene, disclosed by the invention, comprises a light component removing tower, a heavy component removing tower, an extracting and distilling tower and an extractant recovering tower. The invention further discloses the method for extracting, distilling and separating propane and propylene. The device and the method have the advantages that the equipment is simple, the investment is few, the separating effect is great, the cyclic use of an extractant generates no secondary pollution, the running cost is low, propane and propylene, with polymer grade purity, obtained after treatment have great social benefits, and efficient propane and propylene separation is realized.

Description

Technical field

[0001] The invention relates to a device and a method for separating propane and propylene by extractive distillation. Background technique

[0002] Light olefins are very important basic raw materials for petrochemicals. The separation of light olefins such as ethylene and propylene from the corresponding alkanes requires large equipment investment and high energy consumption for traditional industrial separation processes. The conventional method currently used for the separation of olefin and alkane mixtures is cryogenic distillation. Due to the similar boiling points of carbon olefins and alkanes, the production device requires more than 100 contact units and a reflux ratio of up to 10 orders of magnitude. This method not only has high energy consumption, but also The production equipment is expensive. In order to reduce energy consumption and improve separation efficiency, it is of practical significance to develop a new olefin separation process, and it is...

Examples

Embodiment 1

[0037] The device for extractive distillation and separation of propane and propylene in this embodiment includes a light component removal tower 1, a heavy component removal tower 2, an extractive distillation tower 3, and an extractant recovery tower 5;

[0038] The middle part of the light-removing tower 1 is equipped with a light-removing tower raw material inlet, the top of the light-removing tower 1 is equipped with the first outlet of the light-removing tower, and the bottom of the light-removing tower 1 is equipped with a light removal group The second outlet of the sub-column; the middle of the de-heavy component tower 2 is equipped with a de-heavy-component tower raw material inlet, the top of the de-heavy component tower 2 is equipped with the first outlet of the de-heavy component tower, and the bottom of the de-heavy component tower 2 is equipped with de-recombinant The second outlet of the fractionation tower; the upper part of the extractive distillation tower 3 is ...

Embodiment 2

[0043] The extractive distillation device used in this embodiment to separate propane and propylene is the same as that in Embodiment 1.

[0044] In this example, the feed gas for catalytic cracking of a refinery is characterized by 1.5% C2 and lower alkanes, 34% propane, 63% propylene, and 1.5% alkanes above C4. The extractant is a mixed solvent of N-formylmorpholine (NFM) and N-methylpyrrolidone (NMP), and the mass ratio of the two is 4:6. At the same time, the extractive distillation tower 3 in this embodiment is equipped with high-efficiency structured packing 4, the number of theoretical plates is 30, the reflux ratio is 3, the operating pressure is 1.8MPa, and the mass ratio of extractant to raw material is 2. The extractant recovery tower 5 is equipped with high-efficiency structured packing 4, the number of theoretical plates is 10, the reflux ratio is 1, and the operating pressure is 1MPa.

[0045] The catalytic cracking feed gas enters the light-removing tower feedstock ...

Embodiment 3

[0047] The extractive distillation device used in this embodiment to separate propane and propylene is the same as that in Embodiment 1.

[0048] In this example, the feed gas for catalytic cracking of a refinery is characterized by 1.5% C2 and lower alkanes, 34% propane, 63% propylene, and 1.5% alkanes above C4. The extractant is a mixed solvent of N-formylmorpholine (NFM) and tetrahydrofuran (THF), and the mass ratio of the two is 5:5. At the same time, the extractive distillation tower 3 in this embodiment is equipped with high-efficiency structured packing 4, the number of theoretical plates is 80, the reflux ratio is 10, the operating pressure is 2.5MPa, and the mass ratio of the extractant to the raw material is 10. The extractant recovery tower 5 is equipped with high-efficiency structured packing 4, the number of theoretical plates is 40, the reflux ratio is 8, and the operating pressure is 2MPa.

[0049] The catalytic cracking feed gas enters the light-removing tower feed...

Technical field

[0001] The invention relates to a device and a method for separating propane and propylene by extractive distillation. Background technique

[0002] Light olefins are very important basic raw materials for petrochemicals. The separation of light olefins such as ethylene and propylene from the corresponding alkanes requires large equipment investment and high energy consumption for traditional industrial separation processes. The conventional method currently used for the separation of olefin and alkane mixtures is cryogenic distillation. Due to the similar boiling points of carbon olefins and alkanes, the production device requires more than 100 contact units and a reflux ratio of up to 10 orders of magnitude. This method not only has high energy consumption, but also The production equipment is expensive. In order to reduce energy consumption and improve separation efficiency, it is of practical significance to develop a new olefin separation process, and it is...

Examples

Embodiment 1

[0037] The device for extractive distillation and separation of propane and propylene in this embodiment includes a light component removal tower 1, a heavy component removal tower 2, an extractive distillation tower 3, and an extractant recovery tower 5;

[0038] The middle part of the light-removing tower 1 is equipped with a light-removing tower raw material inlet, the top of the light-removing tower 1 is equipped with the first outlet of the light-removing tower, and the bottom of the light-removing tower 1 is equipped with a light removal group The second outlet of the sub-column; the middle of the de-heavy component tower 2 is equipped with a de-heavy-component tower raw material inlet, the top of the de-heavy component tower 2 is equipped with the first outlet of the de-heavy component tower, and the bottom of the de-heavy component tower 2 is equipped with de-recombinant The second outlet of the fractionation tower; the upper part of the extractive distillation tower 3 is ...

Embodiment 2

[0043] The extractive distillation device used in this embodiment to separate propane and propylene is the same as that in Embodiment 1.

[0044] In this example, the feed gas for catalytic cracking of a refinery is characterized by 1.5% C2 and lower alkanes, 34% propane, 63% propylene, and 1.5% alkanes above C4. The extractant is a mixed solvent of N-formylmorpholine (NFM) and N-methylpyrrolidone (NMP), and the mass ratio of the two is 4:6. At the same time, the extractive distillation tower 3 in this embodiment is equipped with high-efficiency structured packing 4, the number of theoretical plates is 30, the reflux ratio is 3, the operating pressure is 1.8MPa, and the mass ratio of extractant to raw material is 2. The extractant recovery tower 5 is equipped with high-efficiency structured packing 4, the number of theoretical plates is 10, the reflux ratio is 1, and the operating pressure is 1MPa.

[0045] The catalytic cracking feed gas enters the light-removing tower feedstock ...

Embodiment 3

[0047] The extractive distillation device used in this embodiment to separate propane and propylene is the same as that in Embodiment 1.

[0048] In this example, the feed gas for catalytic cracking of a refinery is characterized by 1.5% C2 and lower alkanes, 34% propane, 63% propylene, and 1.5% alkanes above C4. The extractant is a mixed solvent of N-formylmorpholine (NFM) and tetrahydrofuran (THF), and the mass ratio of the two is 5:5. At the same time, the extractive distillation tower 3 in this embodiment is equipped with high-efficiency structured packing 4, the number of theoretical plates is 80, the reflux ratio is 10, the operating pressure is 2.5MPa, and the mass ratio of the extractant to the raw material is 10. The extractant recovery tower 5 is equipped with high-efficiency structured packing 4, the number of theoretical plates is 40, the reflux ratio is 8, and the operating pressure is 2MPa.

[0049] The catalytic cracking feed gas enters the light-removing tower feed...

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